Analysis of Inherent Irreversibility in a Variable Viscosity MHD Generalized Couette Flow with Permeable Walls*

The inherent irreversibility in a variable viscosity hydromagnetic generalized Couette flow with suction/injection at the walls has been investigated theoretically. Using a fourth-order Runge-Kutta-Fehlberg integration scheme together with shooting technique, the model equations for momentum and energy balance are tackled numerically. The velocity and the temperature profiles are obtained and are utilized to compute the skin friction coefficient, Nusselt number, entropy generation rate and the Bejan number. The results are presented graphically and discussed quantitatively for several values of thermophysical parameters controlling the flow regime. Our results reveal that a decrease in fluid viscosity enhances dominant effect of heat transfer irreversibility and the imposition of magnetic field damping the entropy generation rate in the flow system.